1. Field of the Invention
The present invention relates to a method of modifying color composition for a color-blind person in a mobile displaying apparatus, and more particularly a method of enabling a mobile displaying apparatus to generate color composition modified for a color-blind person to perceive the same color as a person with the normal color vision.
2. Description of the Related Art
Generally people's color vision for perceiving colors through the light-sensitive receptor cells differs from each other so that they perceive one and the same color differently from each other. The color-blind person particularly has an anomaly of color vision compared to the normal person.
Color blindness is defect of vision affecting the ability to distinguish colors. Color blindness is usually classified into achromatopsia and dichromatism, respectively, which provide a measure of the levels of color blindness; total or the partial color blindness, respectively. The vision mainly concerned with the color, form, distance, and tridimensional extension of objects begins with the impact of light waves on the light-sensitive receptor cells of the retina of the eye. The light-sensitive receptor cells consist of conical photosensitive receptor cells, called cones, functioning in color vision and rod-shaped photosensitive receptor cells, called rods, that are responsive to faint light. The cones also consist of three kinds of cells represented by L (Red), M (Green) and S (Blue), respectively, which are responsive to light waves. The color-blind person has one or more of these three kinds affected so as to prevent normal collecting of color information. The most common dichromatic form of color-blindness, (partial color-blind) has a malfunctioning of the L or M cells so that there is an inability to differentiate between the reds and the greens or to perceive either reds or greens. This phenomenon is shown by the characteristic spectral curve of the cones deviated from the normal region.
Hence, the weak color vision of the dichromatic person must be supplemented by augmenting the stimulation of the cones compared to that of the normal person in order to effectively distinguish colors. An example of this is disclosed in Korean Laid-Open Patent Publication No. 2005-0044114 entitled as “Method and Apparatus for Modifying Color Composition of a Video Display by Considering the Qualities of the Color Vision of a Dichromatic Person”.
FIG. 1 is a flowchart for illustrating the conventional process of modifying color composition of a video display according to the result of evaluating the qualities of the color vision of a user. Referring to FIG. 1, when starting to watch a TV, the user firstly displays a test pattern for color blindness retrieved from a memory in order test the qualities of his color vision in step S10. In this case, the test is performed by using the conventional color blindness test pattern, to which the user responds by operating the input keys of a TV remote control to enter the test result to evaluate his color vision qualities in step S20. If the test result indicates color blindness, its type is also evaluated. If the test result indicates the normal color vision, the gains of the original RGB signals are not modified in step S21, or else the gains must be modified.
If the user is evaluated to have the first-type dichromatism in step S30, the gains of the original G and B signals are reduced to 0.75 times their original values in step S31 because the first-type dichromatism shows the “R” sensitivity reduced to 0.75 times the normal sensitivity. In this case, the modification of the RGB gains is carried out by adjusting the contrast gains, and therefore the gains are normalized to “1” at maximum. This process is also applied to the other types of dichromatism.
Alternatively, if the user is evaluated to have the second-type dichromatism in step S40, the gains of the original R and B signals are reduced to 0.7 times their original values in step S41 because the second-type dichromatism shows the “G” sensitivity reduced to 0.7 times the normal sensitivity. Finally, if the user is evaluated to have the third-type dichromatism in step S50, the gains of the original R and G signals are reduced to 0.5 times their original values in step S50 because the third-type dichromatism shows the “B” sensitivity reduced to 0.5 times the normal sensitivity.
However, such conventional method cannot modify the color composition of a video display so as to fit each individual's color vision differing in the color and degree of color blindness since it employs the fixed gains predetermined for each of the three types of dichromatism.